Gas turbine engine discharge nozzles may include variable area and/or variable direction flaps. Such flaps are substantially planular and rotate between opposed parallel sidewalls of the nozzle.
The flaps must tolerate high temperatures in the order of 1500 F. during operation. It is conventional to supply a liner and cooling air to protect the underlying structure from the high temperature gases. Such liners have usually been relatively massive because of the attempt to use flat surfaces and the relatively thick walls of the liner which are required to resist the pressure of cooling air. Other liners have been massive because of the need to resist buckling caused by temperature differential between the liner and the underlying structure.
The thick and massive walls not only pose the potential of substantial strains, but also add weight not only to the aircraft but to the flap which must be maneuvered.
It is an object of the invention to cool the inner surface of a flap in a manner which imposes minimum weight on a aircraft and minimum thermal and pressure stresses.